FIELD OF THE INVENTION
The present invention relates to apparatus for and method of generating characters for use in displaying data representing operation menu obtained when the user operates some suitable audio-video equipments, such as a television receiver, a video tape recorder or the like.
Heretofore, a television receiver or video tape recorder (VTR) has a menu panel to display data representing operation menu obtained when the user operates the television receiver or video tape recorder so that the television receiver or video tape recorder can become easier to handle. When data representing operation menu is displayed on the menu panel of the monitor, it is customary that a displaying portion is made conspicuous by adding a shade to characters, character strings to be displayed or the like in such a manner as to make the displaying portion conspicuous in a so-called pop-up mode as shown in FIG. 1A or to make the displaying portion conspicuous in a so-called pull-down mode as shown in FIG. 1B.
As a method of adding a shade to character or character strings, it is customary that character patterns having shade pattern added thereto are formed beforehand and stored in a memory, i.e., ROM (read-only memory) in which there are stored data, such as character patterns or the like. Then, these character patterns are selected and displayed on the menu panel of the monitor of audio-video equipments, such as the television receiver or the like when necessary. However, according to the above-mentioned conventional method, the ROM needs a memory capacity more than twice as large as the original one to memorize therein data, such as character pattern, etc., which imposes a serious problem when there are many kinds of characters to be displayed on the monitor.
Another method is proposed to add a shade to characters or character strings by designating a shade pattern as a character displaying attribute code after the shade pattern was defined in such usual fashion as to underline the characters, for example. When however the shade pattern is displayed according to this conventional method, it becomes necessary to prepare 16 shade patterns in total of 1 shade pattern used when the shade pattern is not displayed at all, 4 shade patterns used when the shade pattern is displayed only on one of four peripheral sides of a displaying portion, 6 shade patterns used when the shade pattern is displayed on two displaying portions, 4 shade patterns used when the shade pattern is displayed on three displaying portions and 1 shade pattern used when the shade pattern is displayed on the whole displaying portion.
Therefore, a 4-bit display attribute code is required in order to designate the shade pattern. Since the 4 bit display attribute code is stored in a memory together with a character specifying code for every character, it is unavoidable that a memory, i.e., RAM (random access memory) needs a memory capacity large enough to memorize therein the displaying attribute code and the character specifying code. Further, it is not so easy to set the displaying attribute codes of the shade patterns to every characters.
Furthermore, when a displaying portion is made conspicuous by adding the shade pattern to character patterns or the like, according to the conventional methods, it is unavoidable that the ROM needs a storage capacity large enough to store therein data, such as character patterns, etc., or that the RAM also needs a storage capacity large enough to store therein character codes or the like.